Thread-controlling device for sewing machines



THREAD CONTROLLING DEVICE Fo'n SEWING MACHINES Original Filed Oct. 22, 1935 2. SheetsShect 1 I I I I I J a l l I I I I I l gvwc/wtop' Zonis WifneSS:

Aug. 23, 1938'.

s. zoms THREAD CONTROLLING DEVICE FOR SEWING MACHINES Original Fil ed Oct/ 22, 1935 2 Sheets-Sheet 2 I Sydney Zonis v anew;

- Patented 23,

UNITED STATES.

v 2.128.: mam-commune navrca roa sawr mo momma Sydney Zonis, Bridgeport, Coma, assignato i niacturiru,

The Singer Man Company, Eli! beth, N. 1., a corporation of New Jersey Original application October 22, 1935, Serial No.

Divided and this application June 4,

1937,- Serial No. 146,325

2 Claims. (01. nee-25.4)

This invention relates to sewing machinesand has for its primary object to provide a mechanism of a simple form adapted "to efliciently control one or more needle-threads.

, The present improved thread-controlling mechanismis more particularly adapted for use chine having rotary thread-enchainlng loopers for cooperation with the two vertically reciprocatory and laterally vibratory needles of the machine.

The invention consists in the thread-controlling devices, combinations and arrangement'sof parts hereinafter described in connection with the accompanying drawings, in which:

Fig. l is a front side elevation, with the bedplate partly in section, of a sewing machine'con taining the improved thread-handling mechanism. Fig. 2 represents an enlarged detail view;

partly in section, of an auxiliary tension-device employed for controlling slack needle-thread. Fig. 3 represents a needle-thread pull-off device, 25 in a cross-sectional view 01 the machine bracketarm substantially on the line 3-4 of .Fig. 1. Fig. i represents a vertical section of the machine bracket-arm substantially on the line' 4-4 of Fig. '1 and illustrates the intermittent-tension 30 device in released position. Fig. 5 represents a horizontal section of the intermittent-tension device in closed position. f s

This application is a division of my prior patent application Serial No. 46,071, filed Oct. 23, 35 1935, to which prior application reference may be had for an understanding of details of constructlonof the machine not herein fully described.

As illustrated in the drawings, the present hemstitchlng-machine has the usual frame compivotally sustaining a pair of needle-carriers ll and I2 for'adiustment toward and from each ll other. Carried bytherespectiveneedle-carriers The needle-bar are needles I: and u, in also upstanding guiderods II and I4 vertically reciprocated with the needle-bar.

The guide-rod II passes through a transversely apertured swivel-pingll' Journaled in a bearing 5 boss at the free end of a crank-arm it carried by a horizontally disposed rock-shaft l8 journaled in the bracket-arm head 4. The guide-rod I6 is similarly controlled by a swivel-pin 20" journaled in a crank-arm 2| of a rock-:shaft 22 substantially parallel to the rock-shaft l9 and also journaled in the head 4. As more fully disclosed in the prior U. S. patent to A. H. De Voe, No. 1,940,399, Dec. 19, 1933, the respective rock-shafts l9, and 22 are operatively connected to pitman I rods 23 and 24 deriving endwise movements from a rotary cam 25 secured for rotationwith a spurgear 25' driven from the main shaft 5 to rotate once for three rotations of said main-shaft.-

The machine has the usual piercer mechanism comprising a main piercer-and-shaper 26 carried by a piercer-bar 21 Journaled for vertical reciprocation in the bracket-arm head 4, said piercer being actuated by the usual connections with a horizontally disposed rock-shaft 2| journaled in suitable bearings provided at the rear side of the bracket-arm 3. Clamped'upon the to receive the needles in their narrowly spaced reciprocations. The main-piercer 28 reciprocates once for each needle-reciprocation, butthe relative timing is preferably such that said mainpiercer both descends. and rises in advance of the corresponding movements of the needles. Being carried by the needle-bar, the auxiliary piercer 32 of course reciprocates with the needles, but in a single path.

Cooperatingwiththe needles l3 and l4, are two rotary chain-stitch loopers 38, each having a needlerthread-loop seizing beak and a loopspreading wing. These loopers are carried by alined looper-shafts 34 rotatably journaled in spaced bearing lugs 35' and 35 depending from 50.

the bed-plate I. The looper-shatts 34 have gear connections with a loop'er-actuating shaft 3] ro-p tatably journaled below. the bed-plate i and disposed in substantial parallelism with the'mainshaft 5' and the looper-shafts 34. The looper- IF mechanisms are more specifically disclosed and claimed in my prior patent application Serial No.

46,071, no detailed description thereof herein is deemed essential to an understanding of the present invention.

Referring now more particularly to the needlethread controlling devices upon the machine bracket-arm, the needle-threads are intermittently drawn from a suitable thread-supplyinot shown) by a thread pull-off mechanism comprising a thread pull-off rod 42 vibrated in a path between the spaced members of an inverted U- shaped guide-post 43, secured upon the bracketarm 3 at the rear side thereof and provided with suitable thread-guiding apertures at opposite sides of the vibratory pull-off rod 42. The rod 42 is carried by an arm extending from a collar 44 clamped upon the piercer-actuating rock-shaft Operating in suitably timed relation with respect to the stitch-forming mechanism is an intermittent-tension device comprising a bushing 45 threaded into the front side of the bracketarm 3 and provided at its outer end with a peripheral flange 46, said bushing being adjustably secured by a lock-nut 41. Seated within the bushing 45 is a supporting sleeve 48 provided, intermediate its ends, with a peripheral flange 49 in engagement with the front face of the bushing-flange 46, The sleeve is secured to the bushing 45, for turning adjustment therein, by a setscrew 58, said sleeve having a forwardly extending post 5| threaded upon its outer end to receive an adjusting nut 52. Extending longitudinally of the post 5|, from the outer end thereof, is a slot 53 terminating at its inner end in a post-aperture 54 communicating with the interior of the sleeve 48.

Embracing the post 5| are tension-disks 55 and 56, between which is disposed a threadseparating disk 51. Mounted upon the post 5|, adjacent to the outer tension-disk 55, is a tension-release disk 58 anchored against rotation by having a central web 58 thereof disposed within the post-slot 53. The tension-disks 55, 56 and the intermediate disk 51 are also restrained against rotation, and by a pin 80 extending forwardly from the sleeve-flange 48 throug' ri suitable peripheral notches in said disks. interposed between the adjusting nut 52 and the tensionrelease disk 58 is the usual beehive spring 6| functioning to impose a frictional drag upon the threads passed between the tension-disks 55, 56, at opposite sides of the separating-disk 51.

Endwise slidable within the sleeve 48 is a tension-release pin 62 provided, within the bushing 45, with a flange 63 affording a shoulder engaged by one end of a coil-spring 64 hearing against the inner end of the sleeve 48. The inner end of the pin 62 extends through the bushing 45 into position for engagement by an eccentric or cam 65 carried by the main-shaft 5. The opposite end of the pin 68 is reduced to enter the post-slot 53 for engagement with the release-disk web 59. A light spring 66 is interposed between the tensionreiease disk 58 and the tension-disk 55 to exert a minimum te'nsion upon the threads when the is substantially instantaneously released and applied, the minimum tension imposed by the spring 86 remaining constant, regardless of the maximum-pressure adjustment of the spring 6|.

The threads are suitably directed from the guide-post 43 to the intermittent-tension device above described andthen to the usual threadtensions 61 before passing to the conventional slack-thread controller 68. From said slackthread controller, the threads are led throughtake-up thread-eyes 69, carried by the needlebar, to an auxiliary slack-controlling device, before passing to the respective needles.

Referring more particularly to Fig. 2 of the drawings, the auxiliary slack-thread controller referred to comprises a supporting post 10 suitably mounted upon the front side of the bracketarm head 4. Embracing the post 18 are two spaced pairs of tension-disks H and 12, between which pairs of tension-disks is interposed a coilspring 13 embracing the post 18. The action of the spring 13 is limited by the hubs of cup-shaped guard-members l4 and I5 partly embracing the respective pairs of tension-disks. The guardfnember I4 may be fixedly secured upon the post 18, as by solder or otherwise, while the guardmember I5 is preferably removably secured by a screw 16 threaded into the end of the post 10.

The post 10 is provided with a slot 11 extending from one pair of tension-disks to the other, access to said slot being provided by a threadingslit I8 in the post midway of the length of the Slut 11.

One of the needle-threads is passed between the disks II, the inner of said disks yielding laterally to a pull upon the thread to introduce the thread, through the slit 18, into the slot 11. The other thread is introduced into said slot 11 in the same manner to pass the, thread between the tension-disks I2. The pairs of tension-disks H and I2 impose a mild tension upon the threads, sufflcient to'properly control said threadsv between the take-up 68 and the needles.

The intermittent-tension device is effective to apply its maximum frictional drag upon the threads during the period of each stitch-forming cycle beginning just before seizure of the needlethread loops by the loopers and ending immediately prior to the setting of the previously formed stitches, the final setting of the stitches being effected by the rotating loopers and occurring as the needles begin their descent. During the rising movement of the needles I 3 and I4, the take-up eyes 69 carried by the needle-bar 9 serve to pull up the loops of thread cast off by the loopers 33, and it is to insure this .oop-pulling-up action that the maximum tension of the intermittent-tension device is applied at this time. When the eyes of the rising needles are passing through the work, sufiicient friction may be imposed upon the threads by the work to prevent or retard, momentarily, the drawing of the threads through the needle-eyes by the take-up.

The slack-thread controller accommodates this condition by yielding to the pull upon the threads.

The intermittent-tension device changes its frictional drag upon the threads from maximum to minimum practically instantaneously as .the needles are ending their tip-stroke, so that a minimum tension may be applied during the final setting of the stitches, thereby to avoid thread breakage. upon the loopers is suflicient to effect setting of the stitches, regardless of the fact that very little drag is imposed at this time upon the threads by the tension-devices. The minimum tension remains eflective until the needles have completed their descent.

While the pull-off rod 42 happens, in the present case, to be effective upon the threads during the time that the maximum tension is appiled by the intermittent-tension device, this particular time of operation of the pull-oi1 is merely incidental and is not essential to the successful operation of the machine.- In fact, it is the frictional drag imposed upon the threads by the member of the guide-post l! remote from the thread-supply which insures pulling the The frictional drag of the threads.

threads irom the supply side of the pull-oi! rod.

Having thus set forth the nature of the invention', what I claim herein is:--

1. A thread-controlling device for sewing machines, comprising, a supporting post having a thread-guiding slot elongated lengthwise of said post and with a threading slit transverse to and opening into said slot, a plurality of pairs of thread-tension disks mounted upon said post, yielding means interposed between said pairs of tension-disks, and means limiting separating movement of said pairs of tension disks.

2. A thread-controlling device for sewing machines, comprising, a supporting post having a srnm zoms. 2s 

